Changes in transcription and/or protein synthesis have been postulated a direct causes of aging. The objective of the proposed research is to gain an understanding of the role of RNA metabolism in aging processes in Drosophila melanogaster. Major goals are to provide a detailed temporal analysis of RNA transcription, utilization, and turnover, and to determine the effects of genetic manipulation of these processes on longevity and on male "senile sterility". Initial focus will be on ribosomal RNA (rRNA) and a combination of bio-chemical, cytological, and genetic techniques will be employed to determine: (1) the patterns of rRNA synthesis and degradation, protein synthesis, and cellular ribosome content from eclosion to death first in wild type males and then in genetically altered males which have increased or decreased rates of transcription; (2) the effects of genetic modulation of rDNA content and/or RNA metabolism on the temporal sequence of events associated with spermatogenesis and the onset of male senile sterilty, and (3) the relation of these parameters to longevity.